HR: 1340h
AN: T23A-1220 [Abstracts]
TI: Heat Transport in Fluid Layers Heated From Within and Below
AU: * Moore, W B
EM: bmoore@ess.ucla.ediu
AF: Institute of Geophysics and Planetary Physics, 3806 Geology Bldg.
BOX 951567, Los Angeles, CA 90095-1567, United States
AU: * Moore, W B
EM: bmoore@ess.ucla.ediu
AF: Department of Earth and Space Sciences, 3806 Geology Bldg.
BOX 951567, Los Angeles, CA 90095-1567, United States
AB:
The heat transport scaling relationships for fluids heated from within
and below is established based on numerical calculations of isoviscous
convection at infinite Prandtl number. The internal temperatures scale
in a way that is similar to the internally heated case, but with an
offset equal to the average of the two boundary temperatures,
reflecting the underlying temperature structure of bottom heated
convection. The heat flux through the boundaries scales as a linear
combination of the end-member modes of heat transport, consistent with
the effects of internal heating on the interior temperature. The
boundary layer thicknesses, however, depend on H and Ra in a
non-intuitive way. As the internal temperature increases with the
addition of internal heating, the upper thermal boundary layer
thickens despite the increased temperature drop across the layer (the
reverse is true for the bottom boundary layer). This is inconsistent
with the idea that the boundary layer thickness is controlled by a
stability condition on the local Rayleigh number, which would predict
that the boundary layer would thin as the temperature drop increases.
Deriving boundary layer thicknesses from the scalings for heat flux
and boundary layer temperature drop provides an excellent fit to the
model results and reveals the importance of plumes arriving from the
other boundary layer in establishing the boundary layer thickness.
This suggests that, though widely used, boundary layer stability
analysis is not an accurate description of the processes controlling
boundary layer thickness.
DE: 5418 Heat flow
DE: 8130 Heat generation and transport
DE: 8147 Planetary interiors (5430, 5724, 6024)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting